In general, a cellular or mobile phone, used as a portable terminal device, comprises a stationary side body having operation keys and a microphone, and a movable body, having a liquid crystal image display surface and speaker, connected to the stationary side body by a hinge so that the movable body can be folded to the stationary side body. The cellular phone can be kept in the condition that the movable body is folded to the stationary body, while it can be used to talk over the phone under the condition that the movable body is open with respect to the stationary body.
Further, recently developed cellular phones have various functions. For example, JP-A (Japanese Unexamined Patent Publication)-2002-281135 discloses a cellular phone capable of recording and regenerating sound in stereo. Using this prior art phone, it is possible to talk over the phone with a microphone and speaker as in the usual conversation. Further, in the case of regenerating sound in stereo, the microphone is used as a speaker, and both the speaker which can also act as a microphone, and the original speaker, are used so as to realize a stereo sound regenerating mechanism.
JP-A-2002-164997 discloses a technique in which a device for realizing a hands-free mode is connected to a cellular phone and a plurality of microphones are used to talk over the phone between two or more persons. Further, JUM-A (Japanese Unexamined Utility Model Publication)-7-11076 discloses a cellular phone capable of using a headset.
Further, as a cellular phone provided with a camera has been introduced, it is possible to take a moving picture with the camera attached to the cellular phone. Moreover, there is suggested a cellular phone provided with a recording mechanism. However, in the conventional cellular phone provided with the recording mechanism, since recording in monaural is carried out with a microphone designed for conversation recording, it was impossible to record sound in stereo with the microphone of the cellular phone.